The 1987 winner of the Miss Junior America pageant, Thiessen was a member of the cast of Saved by the Bell (1989–93) and Saved by the Bell: The College Years (1993–94) before she joined Beverly Hills, 90210 (1994–1998). She has made a number of television movies, including She Fought Alone (1995) Sweet Dreams (1996), and Hollywood Ending (2002). She joined the cast of the now-defunct television series Good Morning Miami in 2003.